The floor press develops proper horizontal pushing mechanics. The floor limits range of motion, making it safe for shoulders and simplifies the movement.
Create tension. Pinch your shoulder blades back and down. With your hands just outside shoulder width, grip the bar tightly and try to “break it”. A stable upper back is key.
Make an arrow. As you lower the bar, keep your elbows close to your side creating an arrow shape. Avoid flaring your elbows which will result in a “T” shape.
Press the bar up and back. Lower the bar in a controlled manor, then accelerate the bar in an arch shape (up and back) to the start position.
This exercise has tremendous carry over to other pressing movements and develops upper strength and stability.